Psoriasis is a genetically determined disorder which is characterized by accelerated division and impaired maturation of keratinocytes. The influence of cAMP on keratinocyte maturation and rate of division will be studied. Tissues to be examined are cell lines ME-180 and KB, as well as keratinocytes obtained from newborn mouse skin. Techniques for isolating nuclear acidic proteins and histones from these cells have been developed. The influence of cAMP on the rate of synthesis and degree of phosphorylation of nuclear acidic proteins and histones will be examined in these cells. The assumption is that altered patterns of genetic transcription that occur as the keratinocyte matures are mediated by nuclear acidic proteins and/or histones.